In the absence of DLT, patients were enrolled in the next dose level. If 1 of three patients had a DLT, the cohort was expanded to include six patients. If ≥2 patients experienced DLT, maximum tolerated dose (MTD) was exceeded and further enrollment at that dose level was stopped. MTD was defined as the highest dose level at which ≤1 of 6 patients experienced a DLT. Only DLT that occurred during the first treatment cycle were used to determine the MTD.